The present invention pertains to the field of computer driven printer/plotters particularly designed for producing engineering or other large drawings on paper, vellum, film or other printing media which is drawn through the mechanism from a roll thereof. Typically, the media may have a width from 8 1/2 inches to as much as 3 or 4 feet or more.
With reference to a rectangular coordinate system, the paper or other printing medium is drawn through the printer in the X direction and a thermal inkjet printer carriage is mounted for movement transversely of the paper in what shall be referred to as the Y direction. A sheet of paper or other printing medium is either manually fed or paper is drawn from a supply roll thereof around a platen roller which may or may not be power driven.
Prior art cutter drive arrangements include drive of the cutter carriage back and forth across its path of movement by its own separate drive or the cutter carriage it may De coupled to the printer carriage when cutting is to take place. One such arrangement which involves electromechanical coupling of the cutter carriage to the printer carriage is shown in Pat No. 3,951,252 issued Apr. 20, 1976 to Selke.
Another arrangement which uses electromechanical coupling is disclosed in co-pending U.S. application Ser. No. 07/879,628, filed May 7, 1992 by inventor Ventura Caamano and assigned to the assignee of the present invention.
It is an object of the present invention to provide a means for coupling a cutter carriage to and de-coupling a cutter carriage from a printer carriage without the use of electromechanical coupling.
Accordingly, the present invention provides a cutter drive for a computer driven printer/plotter comprising:
a) a motor driven printer carriage (20) which is linearly moveable transversely across the path of travel of a roll of print media to be cut, and
b) a cutter carriage (40) which is linearly moveable from a parked position transversely across and back across the path of travel of said media to be cut to return to said parked position, said cutter carriage comprising:
1) a support bracket (42), said support bracket having means (46; 50-53) thereon for supporting said carriage for said transverse movement; and PA1 2) a cutter blade (60) rotatably mounted on said support bracket;
a first one of said carriages having a carriage pickup hook (25) affixed thereto, said pickup hook having an inclined upper ramp (26), an inclined lower ramp (27) spaced from said upper ramp in the direction of travel of said first carriage, a pusher surface (32) and a shelf (28) defining a support platform (29) and a lower surface (30); and a second one of said carriages having a pickup arm (80) affixed thereto in the path of travel of said pickup hook for engagement therewith, said pickup arm having an inclined ramp and first and second edges (87, 88) respectively engageable with said first carriage and said pusher surface, said pickup arm being moveable in a first direction from a free position by said inclined upper ramp (26) as said first carriage moves in a first direction toward said second carriage in its parked position, said pickup arm moving to be supported on said platform (29) as said second edge (88) passes the upper end of said upper ramp (26) whereby said pusher surface (32) on said pickup hook engages said second edge (88) on said pickup arm to permit said first carriage to move said second carriage across said transverse path in a second direction, said pickup hook shelf being moved from its position supporting said pickup arm as said first carriage reaches the opposite end of its path of travel and reverses direction to again move in said first direction thereby permitting said pickup arm to return to its free position, said first carriage engaging said first edge (87) of said pickup arm as said first carriage moves in said first direction until said second carriage reaches its parked position and said first carriage again reverses to move in said second direction whereby said lower ramp (27) of said pickup hook engages said inclined ramp (84) of said pickup arm moving it in a second direction away from its free position, said lower surface (30) of said shelf slideably engaging said pickup arm until said first carriage moves away from said parked second carriage and said pickup arm returns to its free position.